Photographic material comprising a quinoxaline as dye bleaching catalyst

ABSTRACT

A PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL FOR THE SILVER DYE BLEACH PROCESS, WHICH COMPRISES ON A CARRIER, IN AT LEAST ONE LAYER AS DYE BLEACHING CATALYST A QUINOXALINE OF THE FORMULA   2-((A)(7-N)-X-CH2-),3-((A&#39;&#39;)(7-N&#39;&#39;)-X&#39;&#39;-CH2-),D,E-QUINOXALINE   WHERE D IS OXYGEN, HALOGEN   -N(-R1)-R2   OR-O-R3 E HYDROGEN, NITRO,-O-R4 OR-COO-R4, R1 AND R2 EACH REPRESENTING HYDROGEN, ACYL OR LOWER ALKYL AND R3 AND R4 EACH REPRESENTING HYDROGEN OR LOWER ALKYL, OR WHEREIN D AND E IN VICINAL POSITION FORM TOGETHER A RESIDUE OF FORMULA -O-(CH2)M-O-, WHEREIN M IS 1 OR 2,X AND X&#39;&#39; EACH REPRESENT ONE ATOM OF AN ELEMENT OF THE 4TH TO 7TH MAIN GROUP OF THE PERIODIC SYSTEM A AND A&#39;&#39; EACH REPRESENT HYDROGEN OR AN ORGANIC RESIDUE, AND N AND N&#39;&#39; EACH REPRESENT THE GROUP NUMBER OF THE ATOM X OR X&#39;&#39;, SO THAT IN SO FAR AS N OR N&#39;&#39; IS 4 OR 5 THE INDIVIDUAL RESIDUES A OR A&#39;&#39; ARE THE SAME OR DIFFERENT AS WELL AS NEW QUINOXALINES OF FORMULA 1 WHEREIN IN CASE X IS OXYGEN OR HALOGEN, ONE OF D AND E IS DIFFERENT FROM HYDROGEN ARE DISCLOSED.

United States Patent US. CI. 96-53 20 Claims ABSTRACT OF THE DISCLOSURE A photographic, light-sensitive material for the silver dye bleach process, which comprises on a carrier, in at least one layer as dye bleaching catalyst a quinoxaline of wherein D is oxygen, halogen,

or O--R E hydrogen, nitro, 0R or -COO-R R and R each representing hydrogen, acyl or lower alkyl and R and R each representing hydrogen or lower alkyl, or wherein D and E in vicinal position form together a residue of formula O-(CH O, wherein m is 1 or 2, X and X each represent one atom of an element of the 4th to 7th main group of the periodic system, A and A each represent hydrogen or an organic residue, and n and n' each represent the group number of the atom X or X, so that in so far as n or n is 4 or the individual residues A or A are the same or different as well as new quinoxalines of Formula 1 wherein in case X is oxygen or halogen, one of D and E is different from hydrogen are disclosed.

The present invention relates to photographic material containing a quinoxaline as dye bleaching catalyst.

According to the present invention there is provided a photographic, light sensitive material for the silver dyebleaching process which comprises on a carrier, in at least one layer as dye bleaching catalyst a quinoxaline of formula N U Tourer-(Am CH X A n' N/ 1 ')1 E wherein D is hydrogen, halogen,

Patented Mar. 12, 1974 ice residue and n and n' each represent the group number of the atom X or X, so that insofar as n or n is 4 or 5 the individual residues A or A are the same or different, as well as new quinoxalines of Formula 1 wherein in case X is oxygen or halogen, either D or E is different from hydrogen.

With reference to the periodic system, the periodic system of elements after Mendelyeev is meant.

X and X may be different but are preferably identical. Amongst the elements of the 4th to 7th main group, those of the 2nd to 4th periods are preferred. X and X may therefore be, for instance, carbon, silicon, nitrogen, phosphorus, oxygen, sulphur, selenium, chlorine or bromine.

In as far as A and A represent an organic residue, these residues may also be combined in a ring, so that A and A for instance form together an alkylene or alkylidene residue.

Quinoxalines of formula CHr-Xt-(Mm N/ 2 xl )1-n may be used, wherein X, represents carbon, nitrogen, oxygen, sulphur or halogen and n represents the group number of the atom X and D, E and A have the specified meaning.

Of special interest for this purpose are kylene or alkylidene residue and D, E, X and n have the specified meaning.

quinoxalines of Satisfactory results are obtained with quinoxalines of formula D and especially of formula Ha-Xr( I)1-= \N/ i l l)1n E wherein A is hydrogen, carboxyl, nitrile, lower alkyl, acyl or lower alkoxy carbonyl and A is hydrogen, methyl, ethyl, acetyl or ethoxy carbonyl, wherein, if n is 4 or 5,

the individual residues A and A are the same or different and D, E, X, and n have the specified meaning.

3 Particularly suitable quinoxalines correspond to formula l W F r-{ Xh- E N CH2-X2(Ar) 7- wherein X, is carbon, oxygen, sulphur or bromine and n has the group number of atom X and D, E and A have the specified meaning.

Other suitable quinoxalines correspond to formula or especially formula wherein X, is carbon, oxygen or bromine, X carbon or oxygen and n has the group number of atom X and D, E, A and n have the specified meaning.

Amongst the quinoxalines of Formulas 5 and 8, especially those with formula are outstanding, wherein D, E, X A and n have the specified meaning.

Of special interest are quinoxalines of formula crn-o-A,

CHz0-A; N

especially however formula Tom-0%.: -on O-A N 2- 3 E and in particular of formula wherein A is hydrogen, methyl or acetyl and A A D and E have the specified meaning.

Amongst the compounds of Formula 12 those of formula / cm-o-A,

CHr-O-Aa N E1 4 O(CH -O-, wherein m equals 1 or 2 and A; has the specified meaning.

Preferential use is made of quinoxaline of formula H -cH=0-A4 CH O.A NJ. 2 I E2 and especially of formula CHz0-A4 CH -0A N r 2 I a wherein E is hydrogen, methoxy, car-boxyl or ethoxy carbonyl and E hydrogen, methoxy or carboxyl, and A and E have the specified meaning.

Quinoxalines with especially advantageous properties for the use according to the invention correspond to formula CH5O.A.|

-CI-I; OA4 N a especially formula CH30--A| OH,OR4 N/ E4 preferably formula \CHz0A -cH OA N/) 1 I l especially formula -CHr-O-A4 N/ CH;-OA4 E4 and more especially formula -CHzOH CH -0H N 2 E4 wherein E D and A; have the specified meaning, E represents hydrogen or methoxy, D hydrogen, methoxy or chlorine and D hydrogen or methoxy.

Insofar as the D and E residues together are not participating in the formation of a dioxano or dioxolo ring, they are preferably in 0 or p position in respect of each other.

If a compound of Formula 1 contains a carboxyl group, this compound may occur in form of free acid, i.e. with an HOOC group or as a salt. According to the conditions of the separation, for instance the selected pH-value or the cation, which shows the salt used for precipitating, the acid group may occur as a C00 cation group, such as for instance --COONa, COOK, -COOLi,

The lower alkyl residues mentioned in the definition of D and E are as a rule alkyl residues with 1 to 5 carbon atoms, i.e. for instance amyl, n-butyl, tertiary butyl, npropyl, isopropyl or especially ethyl and especially methyl residues.

If A represents an alkyl residue it is preferably a straight chained or ramified carbon chain with 1 to 20, preferably 1 to 5 carbon atoms, which can possibly be further substituted with hydroxyl, lower alkoxy, such as CH O- or C I-I O-, halogens such as chlorine or bromine, CN, lower carballcoxy such as -COOCH' or -COOC H --COOH, carbonamide such as CONH -CONHCH or C'ON(C H SH, lower alkylmercapto such as SCH or SC H sulphone such as -SO CH or SO C H hydroxyacyl such as OCOCH or --OCOC H amino and substituted amino groups such as NH -NHCH -N(CH --N(C2 NHCOCH or -NHCOC H As far as both residues A and A particularly both A residues, form an alkylene or alkylidene residue, this contains preferably 1 to 6 carbon atoms, for instance methylene or propylene.

Acyl residues, occurring in the definitions D and A are for instance residues derived from aliphatic carbonic acids with preferably 1 to 6 carbon atoms such as formic, acetic, propi'onic, valerie or capronic acid; aromatic carbonic or sulphonic acids such as benzoic acid, naphthalene carbonic acids, phenyl sulphonic acid, p-toluene sulphonic acid, methoxybenzoic acids, phthalic acid, isophthalic acid or naphthalene sulphonic acids; araliphatic carbonic acids such as phenyl acetic acid, or heterocyclic carbonic acids such as pyridine carbonic acids, furan carbonic acid or thiophene carbonic acid. They may be derived also from hydroxyl groups containing 5- or 6-membered heterocyclic compounds with 1 to 3 nitrogen atoms and possibly other hetero atoms such as 0, S or Se, the hydroxyl group of which reacts analogously to the hydroxyl group of an organic acid. Examples are 2,4,6-trihydroxy-1,3,5-triazine, 2,4-dihydroxy pyrimidine or Z-hydroxy thiazole. Carbonic acids as well as sulphonic acids, just as the heterocyclic hydroxy compounds, may possibly be further substituted as mentioned for the alkyl residue in A Alkoxy carbonyl residues in A originate primarily form low alkyl residue containing ester groups, such as -OOOCH COOC H --COOnC H or -CO- tertiaryC H If A represents an aryl residue, this contains preferably at most two rings such as for instance a benzene, naphthalene or diphenyl residue. These aryl residues can possibly be further substituted as specified for the alkyl group.

The or -6-membered heterocyclic residues with 0-, N- and S-atoms, which occur in the definition of A may correspond for instance to the formulas N if if if U 21.1) o 21.2 N 21.3 s (21.4) o

0 --s I 21.5 J- 21.6) N

Z=lower alkyl.

Quinoxalines with such amidine residues may occur also as a salt, for instance hydrohalogenides such as hydrobromides or hydrochlorides.

The quinoxalines of Formula 1 can be used in a processing bath, preferably the color bleaching bath and/or in one layer of the photographic material as color bleaching catalysts.

They can be applied either on their own or in the presence of other usual color bleaching catalysts. It is also possible that other quinoxalines of Formula 1 are used simultaneously in the color bleaching bath. Finally, quinoxalines of Formula 1 may he used also in conjunction with other bleach promoting measures, such as for instance in conjunction with an irradiation, or by flushing a gas through the color bleaching bath, or by admix organic solvents in the color bleaching bath.

Quinoxalines of Formula 1 can therefore be incorporated in a layer free from photographically bleachable dyestuff. The multi-layer material can therefore, for instance, have an additional gelatine layer containing only the catalyst, which is immediately on the emulsion carrier or between two color layers. In the latter case the layer containing the catalyst acts also as a separating layer. Furthermore, the catalyst can also be incorporated into colloidal silver or organic yellow filter dyestulf containing filter layers, or in coating layers. As protective colloid these filter layers are recommended to contain equally as the layers with photographic dyestuff, some gelatine.

The quinoxalines of Formula 1 can however also be incorporated direct into a layer containing a photographic dyestuif. Altogether the multi-layer material can have the usual composition. With the photographic materials of the specified composition it is possible to produce color photographs in the usual known manner.

The color bleaching catalysts of Formula 1 can however, as already mentioned, be added also for instance to the color bleaching bath where they then exert their action direct. They may also be added to a preceding treating bath, for instance the developer, a hardening bath, a stop bath or a special bath prior to the silver color bleaching bath. Here a certain amount of the used catalyst quantity is absorbed by the photographic emulsion material and retained until it can become effective in the color bleaching bath. Depending on the application, the quantity of catalyst to be applied may vary within wide limits. Generally, for a strong effect an addition of 0.001 to 0.1 g. catalyst to one litre of color bleaching bath of usual composition is suflicient, containing a silver complex former, such as for instance an alkali bromide or iodide or thiourea and possibly an oxidation protective, such as for instance sodium hypophosphite and to attain the required pH a strong organic or inorganic acid, such as for instance hexane sulphonic acid, hydrochloric acid, sulphuric acid, phosphoric acid or sodium bisulphate.

Further objects of the invention are therefore also a photographic, light sensitive material for the silver dye bleach method, containing on a carrier in at least one layer a quinoxaline of Formula 1 as color bleaching catalyst and photographing processing bath, especially color bleaching bath characterized by containing at least one quinoxaline of Formula 1 an color bleaching catalyst.

A further object of the invention is consequently a method for producing color photographic pictures, according to the silver dye bleach method on materials which contain, on a base, at least one silver halide emulsion layer with a photographically bleacha'ble dye, due to exposure and development of the silver image or color bleaching, characterized by the color bleaching being carried out in the presence of at least one quinoxaline of Formula 1 as color bleaching catalyst.

The hitherto known color bleaching catalysts, used in the silver dye bleach method, act on azo dyestuffs of various constitutions in differing manners. Whereas they may be highly effective in one class of azo dyestuffs, they may show with another class only a very slight bleach promoting effect. Therefore, there is a demand for compounds which on their own or combined with others effect a uniform bleaching of all three layer dyestufis of a multilayer material.

It has been found that quinoxalines of Formula 1 are excellently suited to this purpose. They are outstanding due to the favorable position of their redox potentials and good solubility in the color bleaching bath in the required concentrations. Especially where the residues and A-X'CH in Formula 1 represent a hydroxymethyl or acetoxymethyl the quinoxalines of Formula 1 used according to the invention have a good activity and efiect a favorable gradation; furthermore, in their presence and with suitable application, the bleach couplings between the individual layers containing the photographic dyestulf are largely suppressed. The compounds of Formula 1 can also be used as original materials and intermediate products for pharmaceuticals.

Quinoxalines of Formula 1 are preferably made in a known manner (compare J. C. E. Simpson, Condensed Pyridazine and Pyrazine Rings, in A. Weissberger, The Chemistry of Heterocyclic Compounds, J. Wiley & Sons, New York, 1953, 203, etc.) by condensation of an aromatic 1,2-diamine with 1,2-dicarbonyl compound. Instead of the diamine it is also possible to use the corresponding essentially more stable o-nitraniline or the corresponding odinitro compound, which is reduced to the required diamine and then can be converted without intermediate precipitation into quinoxaline. Accordingly substituted benzfuroxanes or their reduction products (benzfurazanes) can also be reduced via intermediate stages into 1,2-diamines (F. B. Mallory and S. P. Varimbi, J. Org. Chem 28, 1656, etc., 1963) and the diamines thus made accessible to be condensed into quinoxalines. The quinoxalines occur as a better yield and higher purity, when carrying out the condensation under nitrogen.

It has been advantageous to synthesize quinoxalines of Formula 1, where X and X are difierent from halogen, from the corresponding 2,3-di-(bromomethyl) compounds by substitution with the required Lewis bases. As Lewis bases, for instance, the following can be used: primary and secondary amines, mercaptides, thiourea derivatives, alcoholates, anions of carbonic acid or of methylene active compounds.

As starting materials for one of the above-mentioned syntheses it is for instance possible to consider the compounds listed in the following table.

1,2-dicarbonyl compounds Dibromo-diacetyl, 1,4-diacetoxybutanedion-2,3, 1,4-dimethoxybutanedion-2,3, 1,4-diethoxy-butanedion-2,3, 1,4-dithio-methoxybutanedion-2,3, 1,4-dithioethoxy-butanedion-2,3.

Lewis bases Na-methylate, Na-ethylate, K-methylate, K-ethylate, K-propylate, K-i-propylate, K-butylate, K-i-butylate, K-tbutylate, K-amylate, K-i-amylate, Na-rnercaptide, K-mercaptide, Na-methylmercaptide, K-methylmercaptide, Naethylmercaptide, K-ethylmercaptide, K-butylmercaptide, Na-butylmercaptide, thiourea, Na-thioacetate, Na-thiopropionate, K-thioacetate, K-thiopropionate, Na-acetate, K-acetate, Na-propionate, K-propionate, Na-butyrate, K- butyrate, Na-caproate, K-caproate, Na-benzoate, K- benzoate, Na-nicotinate, N-nicotinate;

Alkali or earth alkaline salts of pyridine-Z-carbonic acid, pyridine-4-carbonic acid, thiophene-Z-carbonic acid, furane-Z-carbonic acid, phthalic acid,

i-phthalic acid,

terephthalic acid, 4-methyl benzoic acid, 4-amino benzoic acid, 2-amino benzoic acid, 3-chlorobenzoic acid;

Alkali salts of Malonic acid ethyl ester, methyl malonic acid ethyl ester, ethyl malonic acid ethyl ester, butyl malonic acid ethyl ester, benzyl malonic acid ethyl ester, aceto acetic acid ethyl ester, methyl aceto acetic acid ethyl ester, 2- ethyl aceto acetic acid ethyl ester, 2-propy1 aceto acetic acid ethyl ester, 2-butyl aceto acetic acid ethyl ester, 2- benzoyl aceto acetic acid ethyl ester, 4-methyl aceto acetic acid ethyl ester, 4-ethyl aceto acetic acid ethyl ester, 4- butyl aceto acetic acid ethyl ester, 4-phenyl aceto acetic acid ethyl ester, 4-(2-pyridyl)-aceto acetic acid ethyl ester, 4-(3-pyridyl)-aceto acetic acid ethyl ester, 4-(4- pyridyl) -aceto acetic acid ethyl ester, 4-(2-thienyl)-aceto acetic acid ethyl ester, 4-(2-furanyl)-aceto acetic acid ethyl ester, -cyano acetic acid ethyl ester, malodinitrile,

3,6-dimethoxy-1,2-dinitro benzene, 4-methyl-2-nitraniline, 4-methoxy-2-nitraniline, 4-ethoxy-2-nitraniline, 3-ethoxy-2-nitraniline,

2,3-nitro anisol,

4,5-nitro veratrol, 4-amino-3-nitrobenzoic acid, S-amino-Z-nitrobenzoic acid, 2,3-dinitraniline, 3,6-dimethoxy-2-nitraniline, 3,6-dimethoxy-o-phenylene diamine, 4-amino-5-nitro veratrol, 4,5-diamino-veratrol, 4-methyl-o-phenylene diamine, 4-methoxy-o-phenylene diamine, 4-ethoxy-o-phenylene diamine, 2-amino-3-nitroanisol,

2-nitro-3-amino anisol, 3-methyl-4-amino-5-nitro anisol, 3-methyl-4,5-diamino anisol, 2,3-diamino anisol, 4-cyano-2-nitraniline, 4-cyano-o-phenylene diamine, 3-cyano-2-nitraniline, 3-cyano-o-phenylene diamine, 2,3-dinitro-4-methyl anisol, 2-amino-3-nitro-4-methyl anisol, 3-amino-2-nitro-4-methyl anisol, 2,3-diamino'4-methyl anisol, 2,3-dinitro-4-methoxy acetanilide, 2-amino-3-nitro-4-methoxy acetanilide, 3-amino-2-nitro-4-methoxy acetanilide, 2,3-diamino-4methoxy acetanilide, 2-methoxy-4,5-dinitro acetanilide, 2-methoxy-4-amino-5-nitro acetanilide, 2-methoxy-4-nitro-5-amino acetanilide, 2-methoxy-4,S-diamino acetanilide, 2-methoxy-4,5-dinitraniline, 2-methoxy-S-nitro-p-phenylene diamine, Z-methoxy-4-nitro-m-phenylene diamine, 2-methoxy-1,4,5-triamino benzene, 2,3-dinitro-4-methoxy-N-methyl acetanilide, 2-amino-3-nitro-4-methoxy-N-methyl acetanilide, 3-amino-2-nitro-4-methoxy-N-methyl acetanilide,

2,3-diamino-4-methoxy-N-methyl acetanilide,

2,3-dinitro-4-methoxy-N-methyl aniline, 3 nitro-4-methoxy-N -methy1-o-phenylene diamine, 2-nitro-4-methoxy-N -methyl-m-phenylene diamine, 4-methoxy-N -methyl-1,2,3-triamino benzene.

Benzfuroxanes 4(7)-chloro-5(6)-methoxy benzfuroxane, 4(7)-ch1oro-5(6)-ethoxy benzfuroxane, 5 (6)-ch1oro-4(7)-methoxy benzfuroxane, 5(6)-chloro-4(7)-ethoxy benzfuroxane.

Benzfurazanes 4-chloro-5-methoxy benzfurazane, 4-chloro-5-ethoxy benzfurazane, 4-methoxy-5-chloro benzfurazane, 4-ethoxy-5-chloro benzfurazane.

INSTRUCTIONS FOR PRODUCTION General instructions A substituted o-dinitrobenzene derivative is dissolved or suspended in a suitable medium, such as for instance acetic acid, ethyl ester, methanol, ethanol, glacial acetic acid or dimethyl formamide, mixed with 1 to 10 percent by weight of a hydrating catalyst, such as for instance a 10% palladium carbon catalyst and hydrated under normal pressure, possibly with initial heating. After the reaction is terminated, the catalyst is filtered off under N and the filtrate under N is treated with at least the equimolecular quantity of distilled or recrystallized diketone or mixed with a solution of the diketone in a suitable solvent, whereby in most instances a color intensification occurs and the temperature rises. Subsequently the mixture is stirred until the reaction is complete, possibly while heating, and the required substance isolated. The product may be purified by re-crystallization from a suitable solvent, distillation or possibly by chromatography or sublimation.

Instead of the o-dinitrobenzene derivative, it is possible to use in some instances the corresponding o-nitraniline compound.

If the corresponding o-phenylene diamine is easily accessible and in sufiicient purity, it is direct or in form of its hydrochloride in a suitable solvent under nitrogen condensed with the diketone. When using hydrochloride it is recommended to add a suitable quantity of sodium or potassium acetate to neutralize the liberated HCl.

The Redox potentials are determined in the usual known manner by means of polarography. As solvent a mixture of dimethyl formamide-ZN-sulphuric acid in a ratio of 1:1 is used in most instances. The potential is measured against an Ag/AgCl electrode of known potential and then converted to the potential against a standard hydrogen electrode. Whilst in some instances two single electron transits characterized by two polarographic waves occurring are observed, in most other instances only a polarographic wave is observed which then corresponds to the mean Redox potential.

The melting points and results of analyses of all manufactured quinoxalines of Formula 100 are listed in Table I.

(1) 2,3-di-(bromo-methyl) -6,7-dimethoxy quinoxaline 11.4 g. (50 mmol) 1,2-dimethoxy-4,5-dinitro benzene are dissolved in 250 ml. acetic acid ethyl ester and after adding 1 g. of 10% palladium hydrated to carbon at standard pressure, whereby the temperature may rise up to 50 C. H consumption: 7000 ml. of the theory). The catalyst is filtered oif and the filtration mixed under nitrogen whilst thoroughly stirring with 12.0 g. (50 mmol) solid dibromo-diacetyl. After 10 minutes at room temperature the required product commences to separate in a crystalline consistency. The reaction mixture is stirred again for an hour at room temperature and then evaporated under reduced pressure until dry. The residue is dissolved in acetone with heating, treating with charcoal and the filtrate mixed with five times the quantity of iced water. After filtering, 9.8 g. (52% of the theory) of almost colorless crystals are obtained, the IR- and NMR- spectrum of which coincides with the postulated structure of Formula 101.

(2) 2,3-di-(acetoxymethyl)-6,7-dimethoxy quinoxaline 7.6 g. (20 mmol) 2,3-di- (bromo-methyl)-6,7-dimethoxy quinoxaline are dissolved in a mixture of 10 ml. 7M potassium acetate solution and 185 ml. ethanol, and heated to 50 to 60 C. in the course of 3 hours whilst stirring. The precipitated salt is filtered 01f under heat, washed with 50 ml. hot alcohol and the combined filtrates evaporated until dry with reduced pressure. The residue thus obtained is dissolved in ml. methanol in heat and treated with norite. The filtration is mixed with 200 ml. ice water and cooled down to 0 to 5 C. The thus obtained crystalline precipitate is filtered 01f, washed with ice water and dried. Yield: 5.0 g. (75% of the theory). IR- and NMR-spectrum show the bands to be expected from the structure of Formula 102.

(3) 2, 3-di- (hydroxymethyl) -6,7-dimethoxy quinoxaline 3.4 g. (10 mmol) 2,3-di-(acetoxymethyl)-6,7-dimethoxy quinoxaline are dissolved in 160 ml. of an ethanol water mixture of a ratio 1:1 and after adding 2 g. (14 mmol) K CO kept whilst stirring for 20 minutes in a bath at C. The reaction mixture is cooled down to room temperature and then mixed with 800 ml. ice water. During 3 hours stirring at 0 C. a finely crystalline colorless deposit occurs, which is filtered oif and washed with a little ice water. Yield: 2.0 g. (80% of the theory). IR- an NMR-spectra show the bands characteristic for the structure of Formula 103.

(4) 2,3-di-(methoxymethyl) quinoxaline 9.48 g. (30 mmol) 2,3-di-(bromo-methyl) quinoxaline are dissolved in 400 ml. methanol and mixed with a freshly prepared Na-OCH solution in methanolprepared from 1.38 g. sodium and 50 ml. methanol. The reaction mixture is heated for 3 hours whilst stirring and refluxing and subsequently reduced to approximately 14 of its volume under reduced pressure. The residue is poured into water and the solution thus obtained exhaustively extracted with chloroform. After drying of the organic phase over sodium sulphate and evaporation, a brown oil remains which is fractionated in high vacuum. Yield: 2.7 g. (41% of the theory), colorless oil of boiling point 103 to 105 C./0.08 torr, which on leaving to stand solidifies at least partially at 5 C. IR- and NlMR-spectrum coincide with the structure of Formula 104.

(5) 2,3-di-(dimethyl-aminomethyl)-6-methoxy- 7-acetamino quinoxaline 15 g. (38 mmol) 2,3-di-(bromomethyl)-6-methoxy-7- acct-amino quinoxaline are dissolved in 250 ml. ethanol. After adding 95 ml. of 40% dimethylamine, the reaction mixture is heated under reflux for 2% hours whilst stirring. Then ml. of the solvent is distilled under atmospheric pressure and the residue put into 150 ml. ice water. The aqueous solution is extracted three times with 100 ml. methylene chloride each, the combined organic phases are washed twice with 100 ml. saturated NaCl solution each and dried over Cacl treated in heat with norite and finally evaporated under reduced pressure until dry. The remaining 10.3 g. of the raw product (105) are dissolved for cleaning in 100 ml. methylene chloride in heat, the solution treated once again with charcoal and after adding 100 ml. n-hexane cooled down to C. The colorless crystals which precipitate are sucked off, washed with a little ice cold hexane and dried. Yield: 8.1 g. (66% of the theory). IR- and NMR-spectrum coincide with the structure of Formula 105.

(6) 2,3-di-(methylthiomethyl)6-chloroquinoxaline 6.8 g. (20 mmol) 2,3-di-(bromomethyl)-6-chloroquinoxaline are suspended in 150 ml. ethanol and mixed in portions with altogether 33.3 ml. of an alcoholic 1.8 molar KSCH solution and stirred for 3 hours at 50 C. After leaving to stand overnight at room temperature, the reaction mixture is treated with Norite and the filtrate poured into five times the volume of ice water. A brown crystalline deposit is obtained, which is filtered 011 and dried at room temperature in vacuum. Yield: 3.8 g. (67% of the theory). IR- and NMR-spectrum show the absorption to be expected from the structure of Formula 106.

(7) 2,3-di-(2-acetyl-2'-carbethoxy-ethyl) quinoxaline To 60 mmol aceto acetic acid ethyl ester sodium salt in 25 ml. anhydrous ethanolmade from 1.4 g. sodium in 25 m1. anhydrous ethanol and 7.8 g. (60 mmol) aoeto acetic acid ethyl ester-a suspension of 9.5 g. (30 mmol) 2,3-di-(bromomethyl) quinoxaline in 250 ml. anhydrous alcohol is added drop wise, whilst stirring in heat. The solution thus obtained is heated for 3 hours under reflux, whereby the pH value of the solution becomes neutral. The deposit occurring on cooling down to room temperature is separated and the filtrate cooled down to 0 C. Thereby 1.9 g. (15% of the theory) of the required compound occur as colorless crystals. IR- and NMR-spectrum coincide with the structure of the Formula 107.

( 8 2,3 -di- (hydroxymethyl) 6-methoxy-7-amino quinoxaline 2.61 g. (10 mmol) 2,3di-(hydroxymethyD-6-methoxy- 7-acetamino quinoxaline are heated for 2 /2 hours in 100 ml. of a 10% aqueous potassium hydroxide solution in reflux. After cooling down to room temperature, the solution is adjusted with 2n hydrochloric acid to a pH value of 5. The deposit thus occurring is filtered 011 and the filtrate extracted with acetic acid ethyl ester, the organic solution treated with active carbon and from the solution thus obtained with petrol ether 550 mg. of a light brown product are precipitated. For further purification 400 mg. of this product are chromatographed on silica gel with methylene chloride/methanol (9:1) as fluxing agent. JR- and NMR-spectrum coincide with the structure of Formula 149.

(9) 3'-cyano-3-carboethoxy-2,3-cyclopentane quinoxaline 1.0 g. metallic sodium is dissolved in 20 ml. anhydrous ethanol. Subsequently, 4.52 g. (40 mmol) cyanoacetic acid ethyl ester are added and the reaction mixture heated for 12 hours until boiling, whilst thoroughly stirring. Thereby an almost homogeneously yellow solution is obtained, to which is added in a nitrogen atmosphere a solution of 6.4 g. (20 mmol) 2,3di-(bromomethyl) quinoxaline (121) in 200 ml. anhydrous ethanol. The reaction mixture is heated for 3 hours by reflux whilst stirring, whereby the color turns to dark brown. The reaction mixture is cooled down for hours to room temperature and subsequently cooled down to 0 C. The precipitated greyish deposit is filtered oif, washed with cold water and dried: yield 2.5 (47% of the theory). JR- and NMR- spectrum coincide with the structure of Formula 153.

The other compounds listed in Table 1 are made in analogous manner.

TABLE I Analysis (percent) Ascertained Calculated Melting Residue in formula point Compound D 101- fi-OCH;

Br 7 185.6 38. 33 O- 121. 5 57. 48 -O 183.7 57.59 --O- 103-105 66. 04

102- 6-OCH| 03---.-.......--- G-OCHa 04----.------- H 105 B-OCH;

7-NHO CH:

6,7-O-CHa-O- I I I I I I I I I I I I l I n I I I I I I l l l l I I I I l I I I I I I I See footnotes at end of table.

15 EXAMPLE 1 A solution consisting of 3.3 ml. 6% gelatine, 2.0 ml. of a 1% solution of hardener, 2,4-dichloro-6-phenylamino- 1,3,5-triazine-3'-sulphonic acid, 0.5 ml. of a 2.10- molar solution of the compound of Formula 101 in dimethyl formamide and 4.2 ml. of water is poured on to a glass plate of 13 cm. x 18 cm. After drying there is poured over it a solution consisting of 3.3 ml. of 6% gelatine, 3.3 ml. of a silver bromide emulsion, containing 5.3 g. of silver per 100 g. of emulsion, 2.0 ml. of the above hardener, 0.3 ml. of a 1% solution of the bluish-green dyestufi of formula HaCQ-S o zHN H035 SOaH (92115 G 2H5 H O NH--S oQ-om HOQS SOaH carbonate, 4 g. potassium bromide and 0.3 g. benztriazole.

(2) Fixing for 2 minutes with a solution of 200 g. sodium thiosulphate, 10 g. anhydrous sodium sulphite, 20 g. sodium acetate and 10 ml. glacial acetic acid per liter of water.

(3) Rinsing for 4 minutes.

(4) 6 minutes color bleaching with a solution of 10 g. potassium iodide in 1 liter of 1 N sulphuric acid.

(5 2 minutes rinsing.

(6) Bleaching for 2 minutes of the residual silver with a bath containing 150 ml. 37% hydrochloric acid, 25 g. copper sulphate and 30 g. potassium bromide per liter.

(7) Rinsing for Zminutes.

(8) Fixing for 4 minutes as described under (2).

(9) Rinsing for 10 minutes.

After drying the clean picture bleached colorless is obtained with a marked graduated gradation of the wedge used as original.

'EXAMPLE 2 EXAMPLE 3 A photographic material with three color layers contains on a white opaque cellulose acetate film a red-sensitive silver bromide emulsion with the bluish-green dyestuff of formula HOaS- OH HO SOaH 5-0 8 above it an empty gelatine separating layer, then a greensensitive silver bromide emulsion with the purple dyestufl of formula l M HNQNHZQH After a further separating layer there follows a layer with a yellow filter dyestufi or with colloidal silver acting as yellow filter. Above it there is a silver bromide layer with the yellow dyestufi of formula (2. 3) 1103s o-cm N=N-NHC 0- SI 0 3H Ha -0 Sloan 3 k HOaL and a covering layer. All layers are hardened with a halogen triazine compound, such as 2,4 dichloro-6-phenylamino-1,3,5-t1iazine-3'-sulphonic acid.

This copying material is exposed below a stepped wedge one after the other in the three spectral ranges, blue (Wratten filter Kodak 2 B+49), green (Wratten filter Kodak 16+61) and red (Wratten filter Kodak 2X29) and developed and fixed for 7 minutes as described in Example 1. Subsequently bleaching is carried out in a silver color bleaching bath, which contains per liter 27 ml. of 96% sulphuric acid, 10 g. potassium iodide and 10 ml. of a 4.10- molar solution of the compound of Formula 103 in ethanol. After a short rinsing the residual silver is oxidized as described in Example 1 under (6), rinsed and fixed as described above. After thorough washing there is obtained after drying a bleached neutral wedge on white ground, which is parallel to the gradation of the original.

EXAMPLE 4 17 EXAMPLE A photographic material as described in Example 3 is exposed in the three spectral ranges as specified. Subsequently the copy is developed as follows:

(1) Develop for 7 minutes in a bath, containing per liter 50 g. anhydrous sodium sulphite, 0.2 g. 1-phenyl-3- pyrazolidone, 6 g. hydroquinone, 35 g. anhydrous sodium carbonate, 4 g. potassium bromide, 0.3 g. benztriazole and 20 ml. of a 4.10 molar solution of the compound of Formula 128 in water.

'(2) Fix for 2 minutes with a solution of 200 g. sodium thiosulphate, g. anhydrous sodium sulphite and 10 ml. of glacial acetic acid per liter.

(3) Rinse for 2 minutes.

(4) Color bleach for 10 minutes with a solution of 10 g. potassium iodide in 1 liter of sulphuric acid.

(5 Rinse for 2 minutes.

(6) Bleach for 8 minutes the residual silver with a bath containing 150 ml. of a 37% hydrochloric acid, 25 g. copper sulphate and 30 g. potassium bromide per liter.

(7) Rinse for 2 minutes.

(8) Fix for 3 minutes, as described under (2).

(9) Rinse for 10 minutes.

After drying a neutral wedge is obtained with a cleanly white and clearly graduated gradation.

EXAMPLE 6 A glass plate of size 13 cm. x 18 cm. is coated with a solution of the following composition: 3.3 ml. of 6% gelatine, 3.3 ml. of a silver bromide emulsion, which contains 5.3 g. of silver for each 100 g. of emulsion, 1.0 ml. of a 1% solution of the hardener described in Example 1, 0.3 ml. of a 1% solution of the bluish-green dyestuif of Formula 1.1 and 2.1 ml. of water.

After drying a stepped wedge is copied on to the layer thus obtained and the plate then treated as follows:

(1) Develop for 10 minutes in a bath, which contains per liter 20 g. anhydrous sodium sulphite, 1 g. 4methylamino phenol sulphate, 4 g. hydro-quinone, 10 g. an hydrous sodium carbonate, 2 g. potassium bromide and 3 g. sodium rhodanide.

(2) Rinse for 2 minutes.

(3) Oxidize for 2 minutes with a solution of 5 g. of potassium bichromate and 5 ml. of a 96% sulphuric acid per liter of solution.

(4) Rinse for 4 minutes.

(5 Wash for 5 minutes with a solution of 50 g. anhydrous sodium sulphite per liter.

-(6) Rinse for 3 minutes.

(7) Develop for 4 minutes with a solution consisting of 2 g. Calgon, 50 g. anhydrous sodium sulphite, 10 g. hydroquinone, 50 g. anhydrous sodium carbonate, 2 g. 1-phenyl-3-pyrazolidone and 20 ml. of a 1% solution of t-butyl-aminoborane per liter.

( 8) Rinse for 2 minutes.

(9) Color bleach for 6 minutes with a color bleaching bath, containing per liter 27 ml. of 96% sulphuric acid, 10 g. potassium iodide and 10 ml. of a 4.102 molar solution of the compound of Formula 130.

(10) Rinse for 2 minutes.

(11) Bleach for 2 minutes the residual silver as described in Example 1 under (6) 12) Rinse for 2 minutes.

(13) Fix for 4 minutes, as described in Example 1 under (2).

( 14) Rinse for 10 minutes.

After drying, a clean colorless bleached picture of the used Wedge with an opposite gradation is obtained.

Instead of the compound of Formula 130 it is possible to use the compound of Formula 135 or another of the quinoxalines listed in Table I in a suitable photographically inactive solvent miscible with water. If then proceeding as described in this example, a clean colorless bleached 18 picture of the exposed wedge with opposite gradation is again obtained.

EXAMPLE 7 A solution consisting of 3.3 ml. of a 6% gelatine, 3.3 ml. of a silver bromide emulsion, containing 5.3 g. silver per g. of emulsion, 1.0 ml., of a 1% solution of the hardener described in Example 1, 0.3 ml. of a 1% solution of the bluish-green dyestufi of Formula 1.1 described in Example 1, 0.5 ml. of a 4.10- molar solution of the compound of Formula 101 in dimethyl formamide and 1.6 ml. water is cast onto a glass plate of size 13 x 18 cm. After drying, a stepped wedge is copied on to the layer thus obtained and the copy processed as described in Example 1.

After drying a clean and bleached colorless positive picture of the Wedge used as original is obtained.

The compound of Formula 101 can be replaced by the compound of Formula 102 dissolved in dimethyl formamide. If then proceeding as described in this example, once again a clean, colorless, bleached, positive image of the used original is obtained.

With equally good success it is possible to use instead of the compound of Formula 101 the quinoxaline of Formula 134 as acetonic solution.

EXAMPLE 8 A photographic material, as described in Example 3, is exposed in the three spectral ranges. The copy is then processed as follows:

(1) Develop for 7 minutes in a bath, which contains per liter 20 g. anhydrous sodium sulphite, 10 g. anhydrous sodium carbonate, 4 g. hydro-quinone, 1 g. 4-methylamino-phenol sulphate, 2 g. potassium bromide and 10 ml. of a 4.10- molar solution of the compound of the Formula 128 in water.

(2) Fix for 2 minutes with a solution of 200 g. sodium thiosulphate, 15 g. anhydrous sodium sulphite, 25 g. crystallized sodium acetate and 13 ml. glacial acetic acid per liter.

(3 )Rinse for 2 minutes.

(4) Color bleach for 10 minutes in a bath containing 10 g. potassium iodide, 27 ml. of a 96% sulphuric acid and 5 ml. of a 4.10" molar solution of the compound of Formula 128 in water per liter.

(5) Rinse for 2 minutes.

6) Bleach for 8 minutes the residual silver as described in Example 5 under (6).

(7 Rinse for 2 minutes.

( 8) Fix for 3 minutes as described under (2).

(9) Rinse for 10 minutes.

After drying a clean, positive image bleached white of the used original is obtained.

EXAMPLE 9 A glass plate of size 13 cm. x 18 cm. is coated with a solution consisting of 3.3 ml. of a 6% gelatine, 2.0 ml. of a 1% solution of the hardener described in Example 1, 3.3 ml. of a silver bromide emulsion, containing per 100 g. of emulsion 5.3 g. of silver, 0.3 ml. of a 1% solution of the bluish-green dyestulf of Formula 1.1 and 1.1 ml. of water. After drying a stepped wedge is copied on to it (50 Lux, 3 seconds) and the copy processed as follows:

Color bleach for 6 minutes with a solution containing per liter 2.7 ml. of a 96% sulphuric acid, 10 g. potassium iodide and 10 ml. each of a 4.10- molor solution of one of the compounds of Formulae 113, 114, 126 or 136 in ethanol or another suitable photographically inactive solvent, miscible with water.

After two minutes of rinsing the residual silver is oxidized, as described in Example 1 under (6), rinsed and fixed as described above. The copy is thoroughly washed and dried. In all instances a clean, colorless bleached, bluish-green wedge the gradation of which is parallel to that of the original is obtained.

1 9 EXAMPLE 10 HOsS WANG-NE NH! $03K 2 2.0 ml. of a 1% solution of the hardener described in Example 1, 3.3 ml. of a silver bromide emulsion, containing 5.3 g. of silver per 100 g. of emulsion and 0.4 ml. of water, is cast on to a glass plate of size 13 cm. x 18 cm. After drying a stepped wedge (50 Lux, 5 seconds) is copied on it and the copy processed as follows:

Develop and fix as described in Example 1. Color bleach for 6 minutes with a solution containing per litre 10 g. potassium iodide, 27 ml. of a 96% sulphuric acid and 10 ml. each of a 4.10- molar solution of the compound of Formulae 110 or 129 in ethanol or another suitable photographically inactive solvent miscible with water. After brief rinsing the residual silver is oxidized as described above, rinsed and fixed. After thorough washing and drying there is thus obtained in all instances a colorless bleached image, which is clean and a clearly graduated gradation of the original used.

EXAMPLE 1 1 Onto a glass plate of size 13 cm. x 18 cm. is cast a solution consisting of 3.3 ml. of a 6% gelatine, 2.0 ml. of a 1% solution of the hardener described in Example 1, 3.3 m1. of a silver bromide emulsion containing 5.3 g. of silver per 100 g .of emulsion, 0.5 ml. of the yellow dyestuff of formula 11.1 HO S cm -0 o N=N s 0311 cm 2 EXAMPLE 12 Onto a photographic material, as described in Example 10, a stepped wedge is exposed (500 Lux, 10 seconds). The strip is thoroughly dampened with a 1 N sulphuric acid, containing per litre 10 mol of the Compound 130, and subsequently brought into close contact with a bright iron sheet. After short rinsing, fixing is carried out subsequently thorough rinsed. After drying, a silver wedge corresponding to the original is obtained with a color wedge in the opposite direction. If proceeding as described above and oxidizing the formed silver as in Example 5 point (6), rinsing, fixing and once again rinsing, a purple wegde with a gradation in the opposite direction obtained.

What is claimed is:

1. A process for the production of colored photographic images by the silver dyestufif bleaching method, which comprises azo dyestuif bleaching in the presence of a catalyst comprising a quinoxaline of the formula wherein D is hydrogen, halogen,

or --OR E hydrogen nitro, 0R or -C0O--R R and R each representing hydrogen, acyl or lower alkyl and R and R each representing hydrogen or lower alkyl, or wherein D and E in vicinal position form together a residue of formula 'O(CH O, wherein m is 1 or 2, X and X each represent one atom of an element of the 4th to 7th main group of the Periodic System, A and A each represent hydogen, carboxyl, nitrile, unsubstituted alkyl, or alkyl substituted by hydroxy, lower alkoxy, halogen, cyano, lower carbalkoxy, carbonamide, mercapto, lower alkyl mercapto, sulphone, hydroxyacyl,

amino, methylamino, dimethylamino, diethylamino, acetylamino or benzoylamino, acyl alkoxycarbonyl, aryl, aralkyl, amidine, a 5- or 6-membered heterocyclic residue selected from the group consisting of a residue of thiophene, pyrrole, furane, oxazole, benzoxazole, benzthiazole, and pyridine, in free or salt form or said 5- or 6- membered heterocyclic residues substituted by hydroxy, lower alkoxy, halogen, cyano, lower carbalkoxy, carbonamide, mercapto, lower alkyl mercapto, sulphone, hydroxyacyl, amino, methylamino, dimethylamino, diethylamino, acetylamino or benzoylamino, A and A is satisfying the valence bonds of X or X by the combination of the members -H, --COCH and COOC H where X or X is carbon, and n and n each represent the group number of the atom X and X, so that in so far as n or n is 4 or 5 the individual residues A or A are the same or different.

2. Process according to claim 1, which comprises as catalyst a quinoxaline of the formula 3. Process according to claim 2, which comprises as catalyst a quinoxaline of the formula wherein A is hydrogen, carboxyl, nitrile, alkyl, acyl, alkoxycarbonyl, aryl, aralkyl, amidine, possibly in form of salt or a 5- or 6-membered heterocyclic residue with nitrogen, oxygen or sulphur as hetero-atom wherein if n is 4 or 5 the individual residues A may be the same or different, and if n equals 4, 5 or 6, the two A together form an alkylene or alkylidene residue, and D, E, X; and n have the meaning specified in claim 2.

21 4. Process according to claim 3, which comprises as catalyst a quinoxaline of the formula 5. Process according to claim 4, which comprises as catalyst a quinoxaline of the formula wherein A is hydrogen, methyl, ethyl, acetyl or ethoxycarbonyl, whereby if n is 4 or 5, the individual residues A are equal or different and D, E, X and n have the meaning specified in claim 4.

6. Process according to claim 3, which comprises as catalyst a quinoxaline of the formula wherein X is carbon, oxygen, sulphur or bromine and n has the group number of atom X and D, E and A have the meaning specified in claim 3.

7. Process according to claim 4, which comprises as catalyst at quinoxaline of the formula N H 2 a-( z)1-n, N CHzXa(Ag) wherein X, is carbon, oxygen or bromine and n; has the group number of atom X and D, E and A have the meaning specified in claim 4.

8. Process according to claim 7, which comprises as catalyst a quinoxaline of the formula wherein X is carbon or oxygen and n has the group number of atom X and D, E and A have the meaning specified in claim 7.

9. Process according to claim 8, which comprises as catalyst a quinoxaline of the formula CHPXl-(Ama, E wherein A is hydrogen, methyl, ethyl, acetyl or ethoxycarbonyl, D, E, X, and n have the meaning specified in claim 8.

22 10. Process according to claim 8, which comprises as catalyst a quinoxaline of the formula wherein D, E and A have the meaning specified in claim 8.

11. Process according to claim 9, which comprises as catalyst at quinoxaline of the formula N U TCHT-O-Ag CH -O-A N I a E wherein D, E and A have the meaning specified in claim 9.

12. Process according to claim 11, which comprises as catalyst a quinoxaline of the formula -cH,-o-A. N E

wherein A is hydrogen, methyl or acetyl, and D and E have the meaning specified in claim 11.

13. Process according to claim 12, which comprises as catalyst a quinoxaline of the formula N KT -cm-o-m E A -CH2O-Al 1 wherein D is hydrogen, acetylamino, methoxy or chlorine, and E hydrogen, carboxyl, lower alkoxy or lower alkoxy carbonyl, or D and E are in neighboring positions forming together a residue of formula O--(CH O wherein m is 1 or 2, and A, has the meaning specified in claim 12.

14. Process according to claim 13, which comprises as catalyst a quinoxaline of the formula N jlorn-o-Ai CHr-O-A; N 2

wherein E is hydrogen, methoxy or ethoxy carbonyl, and A and D have the meaning specified in claim 13.

15. Process according to claim 14, which comprises as catalyst a quinoxaline of the formula (1 Dr N U Iota-o-a, on OA N/ n 4 Es wherein E is hydrogen, methoxy or carbonyl and A and D have the meaning specified in claim 14.

16. Process according to claim 15, which comprises as catalyst a quinoxaline of the formula wherein E and A; have the meaning specified in claim 15. 17. Process according to claim 15, which comprises as catalyst a quinoxaline of the formula 18. Process according to claim 17, which comprises as catalyst 21 quinoxaline of the formula wherein D is hydrogen, methoxy or chlorine, and A and E have the meaning specified in claim 17.

19. Process according to claim 18, which comprises as 7 catalyst 21 quinoxaline of the formula 24 wherein D is hydrogen or methoxy, and A and E have the meaning specified in claim 18.

20. Process according to claim 19, which comprises as catalyst a quinoxaline of the formula wherein D and B, have the meaning specified in claim 19.

References Cited UNITED STATES PATENTS 3,429,705 2/1969 Piller et a1. 9653 3,443,947 5/1969 Mory et a1. 96--53 3,656,953 4/ 1972 Schlunke et a1. 96-20 2,270,118 1/ 1942 Gaspar 9653 3,443,949 '5/1969 Oeitiker et a1. 9653 NORMAN G. TORCHIN, Primary Examiner R. L. SCHILLING, Assistant Examiner US. Cl. X.R. 96--20, 73, 99 

